During surface mounting of electronic components onto a board, in order to secure accuracy of mounting position, position correction is carried out by a method of image recognition. With the aforesaid method, the accuracy of mounting is improved by correcting an amount of travel of a mounting head carrying an electronic component based upon results of a recognition of the accurate position of the board by sensing a recognition mark set at a recognition point of the board. And it is also improved by recognition of an incorrect positioning of the electronic component which is carried on the mounting head, by picking up the image of a status (e.g. orientation) of the electronic component. Generally, in order to simplify the driving system, a method of moving a board recognition camera together with a mounting head is used in the aforesaid method.
As to the board for surface mounting of the electronic components, there are several kind of boards, such as a board on which plural board patterns are printed so that it can be divided into plural board blocks of the same kind, plural boards of the same kind, and an individual board, and these boards are placed on a board carrier of a surface mounting device. Each board block or board has individual recognition points.
With the conventional method of surface mounting of electronic components, after performing the position recognition of the board by detecting the image of the recognition mark of each board using a camera, the surface mounting operation is carried out to mount electronic components onto each board. With the conventional method, however, since the board position recognition camera and the mounting head move together along plural board blocks or a board only for the purpose of detecting images, the original function of the mounting head (i.e. picking up electronic components from a feeder and transferring these electronic components to the boards) is suspended during the image detection action.
And then, surface mounting action is carried out in which the mounting head repeats the going and returning travel along the board blocks or the board, to pick up and mount electronic components and, during this surface mounting action, the camera does not detect any images at all.
Namely, when observing a specific portion of a board, the mounting head passes that portion plurality times, including during the board recognition (image detection) and then during electronic component mounting.
As a result, the travelling path of the mounting head is extremely complicated and the total travelling distance is long. Therefore, it has been a problem that a tact time (a time period from processing of one board to processing of the next board) is prolonged due to the length of the travelling perod.
The purpose of the present invention is to provide an efficient surface mounting method of electronic components with a short tact time.